In various instruments used in surgery, a transmission of torque or force between two components of the instrument is necessary. The transmission of torque serves, for example, for the rotative drive of a surgical tool while the transmission of force is done in the axial direction. Form-locking connections between the two parts are advantageous for the transmission of torque or force. Such connections occur, for example, in the coupling of a flexible drill shaft with the drilling heads for the boring of marrow spaces in bones.
Such a device with form-locking connections for the transmission of torque and axial force between a drive means and a flexible shaft, as well as between the flexible shaft and a clearing tool, has been disclosed in U.S. Pat. No. 5,720,749 to Rupp. In one embodiment, before the joining of the clearing tool and the flexible shaft through plastic deformation, cams are formed in the cylindrical hollow section of a hollow body on the clearing tool. The hollow body provides axial accommodation for the flexible shaft. Subsequently, the flexible shaft is pressed in the axial direction into the hollow section provided with cams whereby the shaft is radially deformed by the cams and is connected to the hollow body, tangentially by means of a form-lock and axially by means of a press fit. One disadvantage of this connection is that, through the pressing of the flexible shaft into the hollow section with cams, the flexible shaft is significantly deformed by the cams and thus, despite the axial conical centering at the front end, a corresponding concentric coaxial connection is not ensured.
An improved connection is desirably one that preferably provides a form-locking connection for the transmission of torque and axial force in which the joining of the flexible shaft to the hollow body is accomplished, absolutely concentrically and coaxially, by means of a sliding fit in which a rotatively and axially form-locking connection can be produced.